The move was the latest pressure by Republican lawmakers on Saudi Arabia over its race for oil market share with Russia (AFP)

Nearly 50 Republican US Representatives told Saudi Crown Prince Mohammed bin Salman on Wednesday that economic and military cooperation between Washington and Riyadh is at risk unless the kingdom helps to stabilise oil prices by cutting crude output.

“If the kingdom fails to act fairly to reverse this manufactured energy crisis, we would encourage any reciprocal responses that the US government deems appropriate,” said a letter to the crown prince signed by 48 lawmakers.

The signatories make up about a quarter of the Republicans in the US House of Representatives, which is controlled by Democrats.

US President Donald Trump has said he brokered an output cut of 10-15 million barrels per day, but Saudi Arabia and Russia have yet to publicly indicate any agreement on the level or how to distribute reductions among Opec+ members.

Moscow and Riyadh have signalled they could agree to cuts but only if the US and others outside Opec+ chip in.

On Tuesday, the US Energy Department said low oil prices will force companies to gradually cut output by nearly two million barrels per day.

Senate Republicans introduced a bill in March to remove US troops, missiles and defence systems from the kingdom if it does not cut output.

The bill faces an uphill battle, but analysts said threats to Washington’s defence relationship with Saudi Arabia have given the Trump administration another card in its talks with the kingdom.

Trump has also threatened tariffs on Saudi and Russian oil imports, but such measures are opposed by industry groups such as the American Petroleum Institute who say they would increase costs for US refiners.